Separator



at high velocity.

Patented Apr; 3,

PATENT, o F cs sErAas-roa Norwood H. Andrews, Moorestown, N. J., and Walter J. Willoughby, Philadelphia, Pa., as-

signors to American P ulverizing Corporation,

Camden, N. J., a corporation of New Jersey Application September 15, 1932, Serial No. 533,256 n cmms. (01. 209-143) Our invention relates to-separators for separating and grading pulverized material, particularly minerals, upon their discharge from a pulverizing apparatus and more particularly from such pulverizing apparatuses'as are disclosed in our copending applications for Letters Patent of the United States, Serial Nos. 544,772 and 587,268,

j wherein the pulverization of' loose mineral matter is effected by the impact against each other of a plurality of streams of said material directed to a focal point, said streams being impelled at a high speed by a dry gaseous fluid such'as superheated steam under high pressure, in which the pieces to be pulverized are to be carried to the point of impact and in which all theparticles,

both coarse and fine, after impactare discharged from the pulverizer in a stream moving vertically The object of the present invention is to provide a separator for the materials so carried in a vertical stream at high velocity, which easily and eificiently separates the heavier dust particles from the fine sufficiently reduced particles and which delivers a product, the particles of which are exceedingly fine and uniform in size, and to provide such a separator with means whereby the grade or fineness and weight of the particles of powder delivered therefrom may be varied to produce a powder of a predetermined quality or grade.

A further object of this invention is to provide a separator wherein the tailings, separated out from the dust by the separator apparatus are returned gravitationally directly to the pulverizer for further reduction or pulverization.

A further object of this invention is to provide a separating-apparatus in which the speed and direction of the dust-laden carrier gas there-- through may be varied and changed from a direc-' tion substantially parallel to the axis of the separator chamber and substantially straight there- .to the particles borne therein, a motion which is the resultant of a variety of motions, to wit, (1)

a longitudinal motion axially of the cylinder from the bottom to the top thereof, (2) an undulatory motion from the axis toward the sides and then from the sides toward the cener or axis, of he cylinder and (3) a rotary motionrwith the axis of-the cylinder as a substantial axis of rotation.

Further objects of this invention is to impart to the carrier gas traversing the separator chamber a rotary movement, a longitudinal movement as a whole,.vertically through the cylinder and an ,undulatory movement toward and away from the sides of the cylinder, whereby the light particles which are borne out of the separator chamber travel in a substantially spiral path about the vertical axis of the separator cylinder atvariable distances from the axis thereof as the particles move from the bottom to the topof the separator.

A further object of this invention is to deliver the product of an impact pulverizer directly to a separator, said product being delivered in a cara'high rate of speed, and to deflect said stream so that it substantially moves horizontally in all directions radially substantially straight out from the axis of the stream towards and against the side walls of the separator chamber, wherein the carrier atmosphere is expanded, and its speed is reduced, and whereby the heavy particles, impinge against the sides of the separator chamber, their speed is substantially, retarded and they fall by gravity out of said stream to the botom of the separating chamber.

A further object of this invention is to-arrange a plurality of separator chambers in a vertical series, one over the other, and all above the pulverizer, so that the tailings from the separator chamber fall gravitationally back from the upper chamber to the lower chamber and from the lower chamber down'to the surface of the mass of loose material being treated in the pulverizer, thereby making unnecessary the use of the mechanicalflconveyor systems now usually employed to carry the tailings back to the pulverizer fof re-treatment. i

A further object of this invention is to provide a duplex separator wherein first the dust is separated from the heavy unpowered particles and wherein next the heavier particles of dust are separated from the dust which is of the desired fineness.

Further objectsof this invention will appear in the specification and claims below.

Referring to the drawing forming a part of this specification and in which the same reference characters are employed throughout to designate the same parts.

Fig. 1 is a vertical sectional view of our improved separator or series of separators, arranged vertically over an impact pulverizer and wherein the upper surface of the material, under treatment in the pulverizer, forms the bottom or lowin Fig. 1;

Fig. 3 isa vertical sectional view of the means ,for varying the vertical flow of material from the lower chamber to the upper chamber; and

Fig. 4 is a vertical sectional view showing a modified construction.

The impact pulverizer 1 is of the type disclosed in our said applications for Letters Patent of the United States, above mentioned, wherein a substantially circular hollow header. 2 is supplied with dry steam at a high temperature and pressure, and the stream is delivered from said header by jets 3 inwardly projecting from the inner wall of said circular header 2 preferably directed toward a common focus or focal region 4 and discharging through a mass 5 of loose material, such as sand, confined at the sides by a vertical wall 6 (preferably cylindrical) and a bottom wall '7 below the header 2 and provided preferably with a cup or depression 8 below the focal region 4-.

The top surface 5' of the mass 5 in the pulverizer 1 is a free surface below which extends the lower end of the lower separator 9. The vertical wall of said separator 9 is preferably cylindrical with its longitudinal axis vertical and coincident with the axis of the vertical wall 6 constituting the material chamber of the pulverizer. The cylindrical casing 9 of the lower separator is substantially smaller in diameter than that of the circular wall 6 of the material chamber of the pulverizer and may be rigidly connected thereto by brackets 10 so that there is a substantial space between the outer surface of the lower sep- I arator cylinder 9 and the inner surface of the wall 6 of the material chamber, and into this space the loose material to be pulverized may be fed through a chute 11, to maintain the level 9 substantially constant and well above the lower end of the cylinder 10, to substantially seal said lower .end, if and when such scaling is desirable.

ing into the mass 5 form through the mass tubular passages 12 and form and maintain a virtual impact chamber 13 around the focal point 4.

Since the mass 5 of loose material is restrained on all sides except the top, the steam forming the impact chamber 13 and the particles impelled in said streams at high velocity together can move in only one direction, after impact in the impact chamber; to wit, vertically upwardly from the impact chamber 13 through the'delivery tube 14 which is also coaxially arranged with respect to the cylinder 9 and is of smaller diameter than the said cylinder 9 of the lower separator. The

steam from the jets 3 after impact in the impact chamber 13 drives upwardly through the mass 5 and through the delivery tube 14 carrying with it both the dust and the larger heavier pieces which have not been reduced to a powder by the impact. Said columnar stream of steam and mineral matter, after impact, moves upwardly through the tube 14 at a very high rate of speed.

Over and spaced from the top of the tube 14 is a deflector 15 preferably conical and inverted and having its apex coincident with-the axis of the stream. This deflector 15 substantially converts the cylindrical column of rapidly moving steam and mineral matter into a substantially flat stream or moving sheet every particle of which is moving outwardly radially from the axis of the delivery tube 14, that is toward and against the vertical walls 9 of the lower separator.

It is possible, however, to make the casing 9 so high that the velocity of the solid material, discharged from the tube 14, is substantially spent before it can reach the top 9', whereupon the deflector 15 may be omitted and the steam expanding into the relatively large high chamber may be utilized to throw the solid matter laterally to effect a separation of the heavy pieces from the dust.

The upper end 9 of the lower separator 9 is preferably a truncated cone with the smaller, upper end thereof'provided with a flange 16 forming a part of the main opening or duct 16 of the lower separator 9. The upper end of the duct 16 is also provided with a similar flange 16 which terminates the hollow inverted truncated conical portion 1'7 forming the lower end of the upper separator 1'7 which is preferably cylindrical for the major portion of its length and disposed with its axis vertical and in alinement with the axis of the lower separator chamber 9, the deflector 15, the delivery tube 14 and the focal point 4 in the impact chamber 13. .The upper end of the upper separator 17 is provided with a head 1'7" of any suitable form and having a circular concentric opening therethrough and to which is connected the elbow 18', of a duct or tube 18 which discharges tangentially into the top of a cylindrical dust collector 19 preferably of the cyclone type.

Within the upper dust separator 1'7 are a series of bafiles or deflectors, the lower one, 20, being spaced from and above the upper end of the duct 16, in vertical alinement therewith, preferably adjustable vertically with respect thereto as will be referred to again below. This deflector 20 is preferably conical with the apex thereof lowermost and adjacent the duct 16.

Substantially.midway vertically of the casing 17 is an annular bafiie or deflector 21, triangular in cross-section to provide sloping upper surfaces iipon which the separated heavy particles cannot accumulate. The base 21 is a flat annular disc, the outside diameter of which is a little less than the inner diameter of the cylinder 1'7 so that there is a narrow annular space between the baflie 21 and the cylinder 17. This baffle 21 also provides a central circular opening 21' with upwardly diverging walls for the passage therethrough of the dust-laden stream moving through the separator casing 1'7. The baffle 21 may be rigidly mounted concentric with the axis of the cylinder 1'7 on brackets 22.

Above the bafile 21 is a preferably inverted conical bafile 23 also preferably vertically adjustable.

For adjusting the bafiies or deflectors 20 and 23 and maintaining the apices thereof in substantial alinement with the axis of the separator chamber 17, the bailie 20 is provided with a rod 24 which freely slides through the upper. bailie or deflector 23 and through a'lug 25 on the elbow 18' of the conductor 18. It is held in any adjusted position by a set screw 26, and its upper end is provided with a handle 27. The deflector 23 is also provided with extending rods 28 which also slide through openings in the lugs 29 and terminate in handles 30. These rods 28 are retained in any adjusted position vertically by set screws 32.

'- -In addition to the communication between the lower cylinder 9 and the upper cylinder 17 through the duct 16 we preferably provide a by-pass or shunt around the duct 16, said by-pass com-' prising-a tube 32, the lower end of which communicates with the upper end of the cylinder 9 and the upper end of which communicates with the lower end 01 the cylinder 17 through the opening 33, the said tube being arrangedtangential tothe cylindrical wall of the upper cylinder 17 so that when the dust-laden gaseous carrier is delivered through the tube 13 into the upper sepa-.

rator cylinder 1'7, arotary motion so imparted to the fluid carrier in the casing 1'7 will develop cenhousing 34 having a transverse vertically narrow slot 35 therethrough in which is slidably seated a plate 36 having aseries of holes 37, 3'7 and 37 of graduated sizes, the largest, 37, being as large as the inside diameter of the duct 16 and the others progressively smaller, and beyond the smallest, the plate may be imperforate, as at 36'. This plate is slidable in the slot 35 and these holes or openings 37, 3'7, 3'7 therethrough may be manually brought into axial alinement with the duct to permit oi. the desired amount ofcarrier gas to pass through the duct.

When the gate or damper or plate 36 is positioned with the largest hole 37 in registration with the passage through the duct 16, substantially all of the carrier gas moving vertically upwardly into the conical top 9' will'pass directly fromthe separator chamber 9 through the duct 16 into the upper separator cylinder 1'7, where, striking against the lower deflector 20, the gaseous carrier will be directed toward the sides of the cylinder 17. As this carrier gas approaches the intermediate annular deflector 21 it moves toward the axis of the. cylinder 1'7 and away from the vertical side walls of the cylinder 17 so as to pass through the large opening 21' through the ring deflector 21. After passing that, however, it is re-deflected laterally by the tapering sides of the inverted conical deflector 23 away from the axis of the cylinder 1'7 and towards its vertical walls. Above this deflector 23 it again travels inwardly toward the axis to make its exit from the chamber through the dust collector tube 18.

This undulatory movement of the dust-laden carrier toward and then away from the side walls of the cylinder 1'7 causes the dust particles borne in the carrier gas to repeatedly strike against the stationary walls and baiiies of the upper separator chamber, with the result that the speed of the travel 01 the heavier particles of dust is so substantially retarded that they no longer float in the current of carrier gas, but will fall to the bottom of the cylinder 1'7. It is for this purpose that the slot is provided between the outer diameter of the central ring deflector 21 and the inner side walls of the cylinder 1'7 so that any of the heavier dust particles collecting in the top outer halt of the ring 21 will not remain there but will fall to the bottom of the collector chamber 17. Moreover any substantial accumulation of coarse dust in the conical bottom 17 or the upper cylinder will slip and fall back into the lower separator chamber 9 through the duct 16, and. to the surface of the mass 5 under treatment in the pulverizer and forming the bottom wall of the lower separating chamber 9. Thus all the tailings" of both separators are gravitationally returned to the material chamber of the pulverizer for further pulverization.

But in addition to the undulatory movement oi! the carrier gas through the upper dust collector 17, it is frequently desirable to impart to the upwardly moving column of dust-laden gas therein, a rotary movement so as to develop centrifugal force in the particles of mineral matter borne in the carrier gas, to bring more of the heavier particles into speed retarding contact with the walls of the cylinder 17 to produce an exceedingly flne powder.

In order to effect this the slide valve or plate 36 in the duct 16 is provided. With the larger of the openings 36 in the plate in registration with the duct 16 substantially all the carrier gas will pass vertically through the duct 16 into the upper chamber 17 and very little or none through the bypass 32 but as smaller openings in the plate are brought into registration with the axis of the duct 16, more and more of the carrier gas will be diverted to pass through the by-pass 32 and enter the upper dust separating chamber 17 tangentially to the casing thereof and when the passage of the carrier gas through the duct 16 is practically stopped by the imperforate portion of the plate surrounding the relatively small hole 37, then substantially all of the dust-laden carrier gas will be introduced into the upper dust separating chamber through the by-pass 32 and a rapid rotary motion will be imparted to the carrier gas therein.

But the passage through the duct 16 should not be completely closed. The small opening 3'7 should be used to permit of the gravitational return to the chamber 9 of the particles separated out of the carrier in the chamber 17.

Thus by regulating the quantity of the carrier gas permitted to enter the separator 17 through the duct 16, the operator also regulates and con trols the rotary movement of the gas therein. When the carrier gas in the casing 17 is so rotated, the travel of a particle of dust, borne in the carrier fluid from the bottom to the top will be generally speaking, in a spiral course, upwardly but with the radius of the revolution of the particle constantly varying. This radius will be relatively short when it passes through the opening 21, relatively large in passing over the deflector 23, and relatively small as it approaches the openings into the discharge duct 18.

In this manner we have imparted to the carrier gas and to the dust in the separator 17 an udulatory movement toward and away from the axis of the cylinder 1'7, a vertical travel through the cylinder 1'7, and when desired, a rotary or spiral motion around the axis of the cylinder 17, the result of which is that the power borne away through the tube 18 consists only of the most minute particles and all the coarser particles are gravitationally returned to the pulverizer for further pulverization.

The dust-laden gas thus delivered to the dust separator 19 is subjected to the usual collector processes. The said air is generally given a rotary movement in the dust collector by admitting the carrier tangentially to the cylindrical casing whereby the speed of the dust particles is so retarded by their physical contact with the wall that they fall gravitationally out of the whirling current of carrier gas to the bottom of the collector 19, the dust free carrier being then allowed to make its exit from the dust collector through an opening 19' at the top thereof.

The dust colle'ctor 19 may be provided with any suitable gate or arrangement 19" for discharging, at will, from time to time the dust which collects in the collecting chamber.

From the above it will also now be apparent that the position of the lower deflector 20 in the chamber 17 may be and is adjusted with respect to its distance above the upper end of the duct 16 and its distance below the opening 33 of the by-pass in order to insure a proper flow and diversion of the carrier gas through the dust separator chamber 17 and that the position of the upper deflector 15 should be and is also easily adjusted to position the deflector 23 at the right distance from the upper end 17 of the collector chamber and at the right distance above the annular deflector 21.

From the above it will now be plain that the rapidly moving upward columnar stream of dust and insufficiently pulverized materials will be carried in the steam or other gaseous fluid from the impact chamber 13 upwardly through the delivery tube 14 and discharge laterally from the upper end thereof due to the impact of the stream upon the inverted conical deflector 15 and that the heavier particles which have not been reduced to dust will be separated out from the dust-laden particles, and will fall to the top of the mass 5 of the material being treated in the pulverizer, and that the major portion of the dust-laden gas above the deflector 15 may be conveyed to the dust collector through one or the other of the two passages provided by the duct 16 and the tube 32, and that the proportions of the dust-laden carrier through either passage may be varied so that almost all may pass through the duct 16 and almost or all may be caused to pass through this by-pass duct 32.

When, therefore, a complete separation of all the coarser particles is desired, it may be attained by imparting to the column of dust-laden gas moving vertically through the dust separator chamber 17 a rapid rotary movement by admitting substantially all of the dust laden gas through the tube 32 and the centrifugal force developed in the heavier particles causes them to drag against the cylindrical wall of the separator and to fall out of the moving stream of carrier gas with the result that only the most minute, most thoroughly sub-divided of the matter which has been pulverized is borne by the separator 1'7 and reaches the collector 19.

When, however, the finest product of the separator is not desired or needed, then the desired grade of fineness may be obtained by a proper adjustment of the valve or plate 36 and a reduction of the amount of dust-laden gas which is permitted to enter through the by-pass 32 which imparts a less rapid rotary movement to the carrier in the casing 17 and consequently less centrifugal force is developed in the particles and coarser particles are also discharged through to duct 18.

While in the drawing the lower separator chamber 9 is shown to be cylindrical, it will be obvious to those skilled in the art that the shape of the chamber in transverse or horizontal crosssection would not particularly affect its function of separating the coarser insufficiently pulverized particles from the dust and the invention is, therefore, not to be construed as limited to a lower separator chamber which is cylindrical in form.

The upper separator chamber 17 is also shown in the drawing and is frequently referred to herein as cylindrical and it is probable that a cylindrical casing is best adapted for the purposes described. It is obvious that when the by-pass 32 is used to impart a rotary orspiral movement to the dust-laden carrier gas traveling through the separator 17, a cylindrical surface would afford the least resistance to the setting up of such a motion of the carrier. But the separator 17 might be polygonal in transverse cross-section without substantially affecting the function of the device provided the faces of the polygon were relatively small and the angles between adjacent sides of the polygon were not so deep as to provide pockets. The construction of the separator chamber 17 is not to be construed as limited to purely cylindrical form so long as the departure therefrom does not seriously interfere with the movements of the carrier gas therethrough as above described herein.

The apparatus shown in the drawing is adapted for substantially universal use; that is to say, it may be used to pulverize one material to a degree of pulverization which may be desired and the next batch which is run through the apparatus may be of an entirely different material, the resulting product of which may be coarser or finer than the one last above described. The treatment of these different batches for the production of different products may be readily effected by admitting more or less of the dust-laden gas to the chamber 17 through the chute or by-pass 32 to eifect the desired rotary movement to the carrier filling the chamber 17. All this is accomplished by adjusting the slide 36 to reduce the proportion of gas admitted throughthe duct 16. It .will be understood that thegreater the rotary movement is the finer the product will be.

But where the apparatus is intended and is for and is to be used on a uniform material required to be pulverized to a given and invariable degree of fineness, the size of the passage provided by the ducts l6 and the size of the by-pass 32 may be definitely determined and proportioned to produce the desired product with the given material, in which event it would not become necessary to change that relationship or proportion and the damper 16 might be omitted, for the size of the particles of the comminuted matter carried over in the collector 19 will depend, when the same material is used, upon the ratio or proportion that the air tangentially delivered to the chamber 17 bears to the air delivered through the duct 16.

We have discovered that by the use of the apparatus heretofore described and wherein the major portion of the dust-laden gaseous carrier is discharged into the dust-separator through the by-pass 32 to produce a very rapid motion of the fluid in the chamber 17, a powder of a degree of fineness hitherto impossible to obtain commercially. can be readily produced in commercial quantities. And this we believe to be due to the subjection of the dust-laden atmosphere or gas to the three kinds of agitation or motion above described. But the admission of the dust-laden gases into the dust-separator by two different passages, one vertical and the other tangential, is of itself very eflicient in effecting a commercial separation of the dust of the lighter from the heavier dust particles and when the apparatus is operated with a major portion of the gas laden atmosphere entering the dust separator tangentially it may not be necessary to subject the gas traversing the dust separator to the undulatory movement above described as efiected by the battles 20, 21 and 23 so that for a production of a less fine powder product these bafiles in the dust separator chamber 17 may be omitted. Such a modification is shown in Fig. 4 wherein the virtual passage through the duct 16 is greatly reduced by an adjustment of the plate or damper 36 so as to permit a minimum of the gases from the chamber 9 to pass therethrough and to cause the major portion of the said gases to pass through a by-pass 32 with a resultant high rotaryor spiral movement to the carrier gases as that traversed upwardly in the chamber 1'7 to the duct 18'.

Such'of the dust-laden carrier gas as passes upwardly through the relatively small opening 37 (which, however should not be less than four (4) inches in diameter in the ordinary set-up of an apparatus of the type herein described and wherein the inner diameters of the duct 16 and of the duct 32 arein the vicinity of 12 or 13 inches) will move, generally speaking, in a straight line upwardly except that in expanding into the larger chamber the stream may increase in diameter as it progresses upwardly and this-stream will be surrounded by and enclosed within a rapidly moving ring or whirl of the said dust-laden gaseous carrier discharged into the separator chamber 1'7 from the duct 32. In this manner the stream or current in the center of the chamber 17 will soon also be dragged around and a rotary or spiral movement imparted to it in its upward travel, and such rotary movement as above described will cause the heavier particles of dust to be drawn centrifugally outwardly against the side walls of the chamber 17 where the speed of the heavier particles will be so retarded that they will not be borne out of the dust separating chamber with the lighter particles.

Thus it is possible to efiect a very satisfactory separation of the heavier particles of dust from the light particles of dust Without subjecting the air to the action of the baflles 20, 21 and 23 by thus admitting the dust-laden carrier gas into the 'dust separator chamber through the tube, ducts, or passages 16 and 32, the latter being a tangential delivery of the gas to the dust chamber and the former a vertically upwardly delivery of the gas thereto axial of the dust separating chamber.

When so operated, the heavier particles will gravitationally fall downwardly on the sides of the chamber 1 7 and under the conical lower end into the upper part of the duct 16 and may aocumulate on the ledge provided by the damper 36 as shown in Fig. 3. From this point, from time to time, the heavier particles will slip over the edge and drop down through the passage 37 into the lower separator chamber 9' for retreatment by the pulverizing action of the jets and further comminution. Without such a passage for the heavier particles of dust they would quickly accumulate in the lower part of the chamber 17 and choke the operation of the dust separator.

Having thus described our invention, what we claim and desire to protect by Letters Patent of the United States is:

1. In a dust separator system, the combination of a lower separator an upper dust separator di-v rectly over said lower separator, means to vertically project upwardly a stream of dust and coarser particles of mineral matter, in and by a gaseous carrier atmosphere, into said lower separator and towardthe sides of said separator to gravitationally separate said heavier particles from said dust, saidupper dust separator being generally cylindrical in shape, a conduit connecting the lower end of the upperseparator with the top of said lower separator to discharge vertically into said upper separator, means within said upper separator to cause the dust-laden atmosphere, traveling through the upper separator from the bottom to the top thereof, to flow in a path which is alternately toward the sides and then toward the axis of said upper separator, a second conduit connecting the top of the lower separator with the bottom of the upper separator and discharging tangentially into said upper separator and means to adjust and vary the volume of dust-laden atmosphere which is permitted to pass through one of said conduits to inversely vary the volume passing through the other conduit.

2. In a dust separator system, the combination with a lower separator, an upper dust separator directly over said lower separator, means operative to project upwardly vertically a stream of dust and coarser particles of mineral matter, in and by a gaseous carrier atmosphere, into the lower end of said lower separator and to deflect said stream toward the sides of said separator to gravitationally separate said heavier particles from said dust, said upper dust separator being generally cylindrical in shape, a conduit connecting the lower end of said upper separator with the top of said lower separator and discharging vertically into and axially of said upper separator to cause the dust-laden atmosphere to traverse the upper separator from the bottom to the top therec, a second conduit leading from the upper end of said lower separator into the lower end of said upper separator to discharge some of the dust-laden atmosphere from said lower separator tangentially into said upper separator to imaprt a rotary movement to said atmosphere moving upwardly through said upper separator.

3. In a dust separator system, the combination with a lower separator, a dust separator directly over said lower separator, means operative to vertically project upwardly a stream of dust and coarser particles of mineral matter, in and by a gaseous carrier atmosphere, into the lower end of said lower separator and to deflect said stream toward the sides of said separator against which sides the heavier particles impinge and by which the speed of said heavier particles is retarded to gravitationally separate said heavier particles from said dust, said upper dust separator being generally cylindrical in shape, a conduit connecting the lower end of said upper separator with the top of said lower separator, means Within said upper separator to cause the dust-laden atmosphere from said lower separator to traverse the upper separator from the bottom to the top thereof and toflow in a path which is alternately nearer the sides and then nearer the axis of said upper separator, a second conduit leading from the upper end of said lower separator into the lower part of said upper separator to deliver some of the dust-laden atmosphere from said lower separator tangentially into said upper separator to impart a rotary movement also to said atmosphere moving upwardly through said upper separator, and a conduit communicating with the top of said upper separator to convey the dustladen atmosphere to a dust collector.

4. In a dust separator system, the combination of a hollow expansion casing, means to vertically project thereinto a stream composed of a mixture of dust and coarser particles of mineral matter impelled in and by an atmosphere of a dry gaseous medium, a battle in said casing against which said stream impinges and by which it is deflected substantially laterally in all directions radially from the axis of said stream toward the sides of said casing against which the heavier particles impinge to retard the speed of the heavier particles and to gravitationally separate said heavier particles from the dust, said chamber having an opening in the top thereof through which a said medium of steam and dust is conducted out of said casing, a conduit communicatingwith said opening and leading vertically therefrom, means in said conduit for varying the volume of the stream passing therethrough and for varying the volume of said stream flowing therethrough, and a second separator casing vertically over said first-mentioned casing and into which said duct discharges vertically, axially thereof a lower bafile within said second casing over said duct to direct the stream impinging thereagainst radially laterally toward the walls of said casing, an intermediate bafile above and spaced from said lower bafiie and slightly spaced from the walls of said casing to direct the stream toward the axis of said casing, an upper baille above said intermediate ballle and spaced therefrom to redirect the stream outwardly radially toward the sides of said casing, the top of said second casing being provided with a central outlet opening, and a second duct connecting said separators and discharging tangentially into the lower end of the upper separator casing, to impart to the contents of the said upper casing a rotary movement dependent upon the quantity of the gaseous medium admitted through said first mentioned duct.

5. In a dust separator system, the combination of a hollow separator casing, means to vertically project thereinto a stream composed of a mixture of dust and coarser particles-of mineral matter impelled in and by an atmosphere of a gaseous medium, a baiile in said casing against which said stream impinges and by which it is deflected substantially laterally in all directions radially from the axis of said stream toward the sides of said casing against which the heavier particles impinge to retard the speed of the heavier particles and to gravitationally separate said heavier particles from the dust, and a second separator casing vertically over said first-mentioned casing, a conduit connecting said separators and through which said stream is discharged from the top of said first separator casing vertically into the bottom of said second separator casing, a lower baffie within said second casing over said duct to direct the stream impinging thereagainst radially laterally toward the walls of said casing, an intermediate baflle above and spaced from said lower baffle and slightly separated from the wall of said casing, to direct the stream toward the central part of said casing, an upper baille above said intermediate battle and spaced therefrom to redirect the stream outwardly radially toward the sides of said casing, the top of said second casing being provided with a central outlet opening, a dust collector tube in communication with said last mentioned opening, a second conduit connecting said separators and discharging tangentially into the lower part of the upper separator casing, and means to vary the quantity of the said medium delivered to said upper separator through said first conduit to inversely vary the volume delivered through said second conduit.

6. In a dust separator, the combination of a substantially cylindrical casing having a conical lower end tapering downwardly and terminating in an inlet opening, means to conduct to said opening and to discharge thereinto a dust-laden gaseous carrier, an inverted conical deflector mounted within said casing above and spaced from said opening to deflect said gaseous carrier outwardly from the axis of said stream toward the cylindrical sides of said casing, an annular bafile intermediate the ends of said casing, above said conical deflector, and slightly spaced from the walls of said casing to deflect said gaseous carrier inwardly toward the axis of said casing, the said annular bafile in cross-section being substantially triangular with the apex of said triangle uppermost of said baffle, an inverted conical deflector between said annular balile and the top of said casing to re-direct' said gaseous carrier outwardly toward the walls of said cylinder, the upper end of said casing being provided with a delivery opening through which the dust-laden atmosphere is discharged from said casing, and means to independently adjust said inverted conical deflectors respectively near the top and 7. In a dust separator, the combination of a substantially cylindrical casing having a conical lower end tapering downwardly and terminating in an inlet opening, a conduit connected to said opening and to discharge thereinto a dust-laden gaseous carrier into said casing vertically, axially thereof, an inverted conical deflector mounted within said casing above and spaced from said opening to deflect said gaseous carrier outwardly from the axis of said casing toward the cylindrical sides of said casing, an annular bafile, slightly spaced from the walls of said casing and positioned above said conical deflector to deflect said gaseous carrier inwardly toward the axis of said casing, the said annular baffle in cross-section being substantially triangular with the apex of said triangle uppermost, an inverted conical deflector between said annular bafile and the top of said casing to re-direct said gaseous carrier outwardly toward the walls of said cylinder, the upper end of said casing being provided with a delivery opening coaxial with the axis of the easing and through which the dust-laden atmosphere is discharged from said casing, means to independently adjust said inverted conical deflectors respectively near the top and bottom of said casing longitudinally axially of said casing, and a second conduit to also deliver dust-laden gaseous carrier to the lower part of said casing tangentially to said casing to impart a, rotary movement to the gaseous carrier traversing said casing upwardly.

8. In a separator system, the combination of a hollow substantially cylindrical casingforming an expansion and separator chamber, means to project a columnar stream of broken mineral and mineral dust in an atmosphere of a dry gaseous medium, into said chamber, vertically upwardly through the bottom of said chamber, said stream being substantially coaxial with the vertical axis of said cylinder, means in the path of said stream and against which said stream impinges to deflect said stream substantially radially outwardly from the axis of said stream in every direction substantially radially from said axis toward and against the inner wall of said chamber to substantially reduce the velocity by impact of the insufiiciently reduced unpulverized particles of mineral matter, whereby the velocity of said atmosphere so entering said chamber is reduced by expansion in said expansion chamber, and the heavier particles fall by gravity to the bottom of said'chamber, a conduit connected to the top of said chamber through which the dustladen atmosphere leaves said chamber and means to vary at will the flow of said stream through said conduit, a dust separator comprising a substantially cylindrical casing located substantially vertically over said first mentioned casing with its axis in alinement with the axis thereof and in communication with the upper end ofsaid conduit, means within said upper dust separator chamber to cause said dust-laden atmosphere to travel through said chamber from the bottom to the top thereof and in a direction alternately outwardly and inwardly away from and toward the vertical axis of said dust'separator, a second conduit to transfer a portion of said dust-laden atmosphere from said first-mentioned separator to said upper' separator to a point near the bottom of said dust separator and to discharge tangentially into said second separator, to impart to said upwardly rising column of dust-laden atmosphere a rotary movement around the axis of said dust separating chamber whereby the heavier particles fall by gravity to the bottom of said dust separator and means to conduct said atmosphere laden with the lighter dust particles away from said dust separator.

9. In a separator, the combination of a substantially cylindrical dust separator casing, a source of dry gaseous carrier fluid with minute particles of dust fioatingly carried thereby, a conduit connecting said source with the interior of said casing at the bottom of the latter for conducting said dust-laden carrier from said source through the bottom of said casing vertically upwardly, means to impart to the carrier an undulatory course, alternately from the axis of said casing toward the sides thereof and from the sides back toward said axis throughout its travel vertically through said casing, means communicating with the top of said casing to conduct said carrier and the dust particles remaining therein out of the top of said casing and a supplemental conduit also connecting with said source and with the interior of the said casing near the bottom of the latter and discharging tangentially to the interior surface thereof for also delivering dust-laden carrier thereto, the carrier fluid so tangentially delivered being operative to impart a rotary movement to all of the carrier fluid filling said casing, about the axis of said casing.

10. In a dust separator system, the combina tion of, a lower separator casing, means to vertically project therein a stream composed of a mixture of dust and of heavier particles of mineral matter driven at a high velocity in and by a gaseous carrier atmosphere and toward the' separator casing, a conduit connecting they lower end of said upper separator casing with the top of said lower casing, means within said upper casing to cause the dust-laden atmosphere entering the bottom of said upper casing from said lower casing to traverse said upper casing from the bottom to the top thereof, and to flow in a path which is alternately toward the sides and then toward the axis of said upper chamber during its vertical travel through said uppercasing, means to vary the quantity of dust-laden atmosphere which is permitted to-pass directly from the top of said lower casing into the bottom of said upper casing, and a second conduit leading from the upper part of said lower easing into the lower part of said upper casing to deliver dust-laden atmosphere from said lower casing tangentially into said upper casing to impart a rotary movement also to said atmosphere moving upwardly through said upper casing.

11. In a dust separator system, the combination of a lower separator casing, means to project thereinto a stream composed of a mixture of dust and heavier particles impelled at a high velocity in and by a-gaseous carrier, vertically and also towards the sides of the casing against which sides the heavier particles strike and by which the speed is retarded to gravitationally separate said heavier particles from the dust, a substantially cylindrical. dust separator casing vertically over said first-mentioned casing, a conduit conmeeting the lower end of said separator chamber with the top of said lower casing to discharge some of the dust-laden carrier gas from said lower chamber into said dust collector chamber vertically axially of said upper casing, a second conduitleading from the upper part of said hollow casing and connected tangentially to the lower end of said dust separator casing 'near the bottom thereof and above the point at which said first conduit is connected to said separator casing whereby some of the dust-laden carrier gas from said lower casing is delivered tangentially through, said second conduit into said up- CERTIFICATE O CORRECTION.

Patent No. 1,953,058. April 3, 1934.

I NORWOOD H. ANDREWS, ET AL.

ii is hereby certified that error appears in the printed specification-0f the above numbered patent requiring correction as follows: Page 1, line 59, for "cener" read center; and same page and line, for "he" read the; page 5, iiue 128, claim 2, for "imaprt" read impart; page 6, iines 24 and 25, claim 4, for "said medium of steam" read stream of said medium; and that the said Letters Patent should he read with these corrections therein that the same may conform to the reeord oi the ease in the Patent @iiiiee.

Signed and seuied this 115th day of Ii/iey, A. D. 1934.

Bryau B/i. Betiey (Seal) Acting Commissieuer of Patents. 

